A steering control valve of the type described is shown in DE-PS 27 39 405, the U.S. counterpart being Tobias U.S. Pat. No. 4,387,737.
The operation is conventional in that friction of the vehicle front, or steered wheels on the ground result in torsional twist of the torque rod which causes relative rotation between valve elements to permit pressure flow to one side of a double acting servomotor, while exhausting the other side, dependent on direction of steering, to actuate a steering mechanism.
Another arrangement for operation is shown in Elser U.S. Pat. No. 4,198,898 (DE PS 27 39 405).
The torsion section of the torsion rod primarily determines the overall length of the steering valve. However, since the respective ends of the torsion rod must connect with the torsion area, the overall length necessarily becomes larger. A specific length is necessary in order to take into account the input shaft or member and the output shaft.